Supply device for supplying an electronic circuit

ABSTRACT

A device for supplying an electronic circuit with a clock signal having a dock frequency includes a frequency actuator that generates the clock signal in accordance with a frequency setting according to a regulation mechanism. A control module selectively applies to the frequency actuator a first frequency setting or a second frequency setting that is higher than the first setting. An adaptation module modifies the regulation mechanism in accordance with the applied setting.

RELATED APPLICATION

This application is a U.S. nationalization of PCT Appl. No.PCT/FR2013/051433, filed Jun. 19, 2013, and published as PCT publicationNo. WO 2013/190236 on Dec. 27, 2013.

TECHNICAL FIELD

The invention concerns a supply device for supplying an electroniccircuit with application of a clock signal.

BACKGROUND

When it is desired to minimize the energy consumption of a synchronousdigital electronic circuit for which timing is provided by a clocksignal, while maintaining its performance, it is known to apply to thatcircuit a clock frequency adapted to a given supply voltage. By“synchronous circuit” is meant a “circuit for which timing is providedby a clock”.

It has moreover been proposed to adapt the clock frequency according tothe performance desired for the system, and also to modify the supplyvoltage, a technique known under the acronym DVFS (for “Dynamic Voltageand Frequency Scaling”).

These techniques are applied in particular in the case of GALSarchitectures (GALS standing for “Globally asynchronous LocallySynchronous”), in which the system concerned is divided into differentVFIs (VFI standing for “Voltage Frequency Island”). Such architecturesare for example produced in the form of SoCs (SoC standing for “Systemon Chip”).

The variable supply voltage to apply to an electronic circuit isgenerated by a module named “voltage actuator”, for example inaccordance with the technique referred to as “Vdd-hopping”, described inthe paper “A power supply selector for energy- and area-efficient localdynamic voltage scaling”, by S. Miermont, P. Vivet and M. Renaudin, inLecture Notes in Computer Science, Volume 4644, pages 556-565, 2007.

As regards the clock signal of variable frequency to apply to theelectronic circuit, this is generated by a module referred to as“frequency actuator”; such a frequency actuator is for example producedin the form of an FLL (for “Frequency Locked-Loop”) or in the form of aPLL (for “Phase Locked-Loop”).

Such frequency actuators are produced in the form of a system operatingin a closed loop which includes in particular a controller influencingthe variable generated according to the measured error (differencebetween the variable measured and the setting) and according to acontrol law.

SUMMARY

The invention provides a supply device for supplying an electroniccircuit with application of a clock signal having a clock frequency,comprising a frequency actuator designed to generate the clock signalaccording to a frequency setting using a regulation mechanism, as wellas a control module designed to selectively apply to the frequencyactuator a first frequency setting or a second frequency setting higherthan the first setting characterized by an adaptation module designed tomodify the regulation mechanism according to the applied setting.

The regulation mechanism may thus be adapted to the applied setting,which makes it possible to obtain differentiated processing depending onwhether the new setting is directed to an increase or a decrease infrequency.

The response time of the frequency actuator may thus be variableaccording to the sign of the frequency variation imposed by the newsetting relative to the former setting.

The adaptation module then enables that response time to be increased ordecreased respectively depending on whether the input setting isdirected to an increase or a decrease in frequency.

In other words, the adaptation module may modify the regulationmechanism such that the response time of the frequency actuatorincreases or decreases respectively depending on whether the appliedsetting increases or decreases.

The response of the frequency actuator is thus differentiated accordingto the direction of variation of the frequency setting.

The frequency actuator comprises for example a controller receiving anerror signal obtained by difference between the frequency setting and ameasured frequency of the clock signal. The frequency actuator may alsocomprise an oscillator controlled by a control signal generated by thecontroller; the oscillator then for example generates the clock signalin this case.

According to a possibility for an embodiment, the adaptation module maycomprise means for determining a gain of the oscillator by measurementof at least one value involved in the regulation mechanism and theadaptation module may then be designed to modify the regulationmechanism according to the determined gain. This makes it possible toadapt the regulation mechanism taking into account in real time thevariations in the oscillator gain.

For example, when the controller is designed to apply a gain to theerror signal, it can be provided for the adaptation module to bedesigned to control the gain applied by the controller according to thedetermined gain.

More generally, it may be provided for the adaptation module to bedesigned to modify an operating parameter of the controller. This is aneffective and generally simple manner of implementation for the purposeof modifying the regulation mechanism.

As already stated, the controller may be designed to apply a gain to theerror signal. The adaptation module is for example designed in this caseto control the gain applied to the error signal.

In practice, it may be provided for a selector controlled by theadaptation module to be designed to selectively apply the error signalto a multiplier from among a plurality of multipliers.

According to another possibility, which may possibly be combined withthe aforementioned gain control, the controller may comprise a memorydesigned to store a control value and the adaptation module may then bedesigned to force the memory to a predetermined value on detection of asetting jump. As explained below, this may enable faster convergencetowards the setting.

According to a possibility for an embodiment, the device according tothe invention may further comprise a voltage actuator designed togenerate a voltage according to a voltage setting, adapted to thefrequency setting, on application of that frequency setting to thefrequency actuator.

The frequency and voltage actuators are thus synchronized.

BRIEF DESCRIPTION OF THE DRAWING

Other features and advantages of the invention will better appear onreading the following description, made with reference to theaccompanying drawings in which:

FIG. 1 represents a general context in which the present invention maybe implemented;

FIG. 2 represents the main components of a frequency actuator inaccordance with the teachings of the invention;

FIG. 3A represents a first example embodiment of the controller of FIG.2;

FIG. 3B represents a variant embodiment of the first example embodiment;

FIG. 4 represents a second example embodiment of the controller of FIG.2;

FIG. 5 represents a third example embodiment of the controller of FIG.2;

FIG. 6 represents a fourth embodiment of the invention.

DETAILED DESCRIPTION

As can be seen in FIG. 1, a supply device 1 for supplying an electroniccircuit 8, for example a voltage frequency island (or VFI) of a GALSarchitecture, comprises a control module 2 which generates a voltagesetting V_(set) and a frequency setting F_(set).

These settings are generated according to the desired performance forthe electronic circuit 8, for example on the basis of instructionsreceived and a date limit for their execution by an operationcoordination module for different islands (not shown).

The voltage setting V_(set) is applied to a voltage actuator 4 whichgenerates, according to the voltage setting V_(set), a voltage V_(appl)applied to the electronic circuit 8.

The frequency setting F_(set) is applied to a frequency actuator 6 whichgenerates a clock signal H at a frequency F_(appl) determined on thebasis of the frequency setting F_(set) as explained below. The clocksignal H is applied to the electronic circuit 8.

The settings V_(set), F_(set) applied at a given time are such that theyenable fault-free operation of the electronic circuit 8.

Thus, in order to pass from a first pair of values (voltage, frequency)₁to a second pair of values (voltage, frequency)₂, the actions of thevoltage and frequency actuators must be synchronized, in particular whenthe voltage and the frequency are modified within a determined timeslot.

These pairs of values may be determined in advance for a given circuit,for example according to prior investigations carried out on circuits ofthis type. As a variant, these values may be determined during acalibration phase during which, for each applied voltage, the operationof the circuit is tested for a plurality of envisioned clockfrequencies, the highest frequency giving fault-free operation beingchosen.

Settings V_(set), F_(set) adapted to fault-free operation are also usedwhen modifications to these settings are made. For example, on a settingchange or jump corresponding to a frequency increase, the voltageadapted to the highest frequency encountered during the jump is alwaysapplied, then the new frequency is applied once the voltage jump hasbeen made.

The temporal response from the output of a conventional system to achange in setting is however not always adapted to the differentsituations encountered in operation. Below, “response” means the“temporal response of the output of such a system”.

Thus, for example, the response of the system in closed loop as a wholemay be influenced by phenomena such as the variability in themanufacturing process or variations in temperature encountered.

The constraints to comply with by the frequency generated may moreoverdiffer according to the operational phases of the system: in a phase offrequency decrease (new setting less than the prior value), exceedanceof the new setting (downwards) can be accepted, whereas such exceedanceis unacceptable in the case of an increase in the frequency (new settinggreater than the preceding setting) since it could lead to operatingfaults due to the use of a clock frequency greater than that intended(and for which an adapted voltage is applied to the circuit).

FIG. 2 represents an example embodiment of the frequency actuator 6.

As already indicated, the frequency actuator 6 generates a clock signalH at a frequency F_(appl) on the basis of a frequency setting F_(set).

The frequency actuator 6 comprises a sensor 16 which measures thefrequency of the clock signal H and generates a signal representing themeasured frequency F_(meas). When the information supplied by the sensoris numerical (that is to say a number), the sensor 16 is typically acounter which produces at its output the number of clock pulses measuredin relation to the clock signal H over a predetermined time.

The frequency actuator 6 also comprises a subtracter 10 which determinesthe disparity (that is to say the difference) between the measuredfrequency F_(meas) and the frequency setting F_(set) and generates anerror signal E representing the computed disparity.

The frequency actuator 6 comprises a controller 12 which receivers theerror signal E and which generates, on the basis of that error signal Eand according to a control law, a control signal U for the system 14 tocontrol, here a DCO (DCO standing for “Digitally ControlledOscillator”).

As referred to previously, a disparity or exceedance of the new settingis tolerated when it entails a decrease in frequency, but such anexceedance is unacceptable in the case of a setting entailing anincrease in frequency.

The error signal E, in particular its sign, makes it possible todetermine whether the exceedance concerned is a decrease or an increasein the frequency, and to provide actions (governed by the control law)to avoid possible operating faults of the circuit 8 due classically tothe exceedance of the frequency response of the actuator 6 relative tothe setting. The digitally controlled oscillator 14 comprises adigital-analog converter and a VCO (VCO standing for “Voltage ControlledOscillator”). The digitally controlled oscillator 14 thus generates anoutput signal of which the frequency is controlled by the control signalU: that output signal is the clock signal H generated by the frequencyactuator 6.

The notation K_(DCO) will be used below in relation to the gain of theoscillator 14.

It is to be noted that, in the embodiment described here, the signalsrepresenting the different variables F_(meas), F_(set), E and U aredigital words and the controller 12 in particular is thus a digitalcircuit. As a variant, it could naturally be provided that some of thesignals, and therefore possibly the controller, be produced in analogform.

FIG. 3A represents a first example embodiment of the controller of 12 ofFIG. 2.

In this embodiment, the error signal E is applied selectively to amultiplier (for example that of coefficient K₁ in FIG. 3) from among aplurality of multipliers 34 (here three multipliers with respectivecoefficients K₁, K₂, K₃) by means of a selector 32 controlled by anadaptation module 30. A version in which the signal E would be appliedto all the multipliers 34 and in which the selector 32 controlled by anadaptation module 30 would choose one of the output signals from themultipliers 34 may also be provided, see FIG. 3B.

Returning to the embodiment of FIG. 3A, the output from each multiplier34 is applied to an adder circuit 36 which also receives as input itsown output signal, delayed by a time determined by passage through amemory 38 provided for that purpose.

Such a controller is of integrator type and at the time k generates asoutput a control signal U(k)=K_(i)·E(k)+U(k−1),

where U(k−1) is the control signal at the time (k−1) and K_(i) is thecoefficient of the selected multiplier.

It is understood that the value of the parameter K_(i) influences on thetime taken by the controller 12 to generate a control signal U whichleads to a signal frequency of clock H equal to the setting F_(set)(that is to say a null error signal E), since the value of K_(i)determines the magnitude of the variations in the control signal U ateach time according to the formula which has just been given.

A high value of the parameter K_(i) thus leads to a fast variation inthe control signal U, which may go as far as an exceedance of thesetting (even though the signal will end up converging towards thesetting since the exceedance thereof leads to a change in sign of theerror signal E).

It is furthermore to be noted that the gain K_(DCO) of the oscillator 14is variable according to the operating conditions (such as thetemperature) and may thus also have an effect on the response time ofthe looped system (since an error signal E induces a modificationK_(i)·E of the control signal U and thus a modification K_(KDCO)·K_(i)·Eof the frequency F_(appl) of the clock signal H).

It may be provided for the adaptation module 30 to control the selector32:

so as to apply the multiplier of coefficient K₁ to the error signal Ewhen the change in setting F_(set) corresponds to a decrease in thedesired frequency;

so as to apply the multiplier of coefficient K₂ (with K₂<K₁) when thechange in setting F_(set) corresponds to an increase in the desiredfrequency and when the ambient temperature T is greater (or, accordingto a possible variant, lower) than a predetermined threshold T₀.

so as to apply the multiplier of coefficient K₃ (with K₃<K₂) to theerror signal E when the change in setting F_(set) corresponds to anincrease in the desired frequency and when the temperature T is less(or, according to the variant which has just been mentioned, greater)than the predetermined threshold T₀.

The multiplier coefficients K₁, K₂, K₃ are for example predeterminedaccording to the operating values provided for the system. These valuesmay come from an off-line calibration phase or be produced duringoperation of the system. The use of these coefficients makes it possibleto vary the response time of the frequency actuator according to thesign of the frequency variation imposed by the new setting relative tothe former setting.

The adaptation module 30 determines the control to apply to the selector32 for example according to the error signal E (which gives whether thenext frequency modification will be a frequency decrease or a frequencyincrease) and a measurement of the ambient temperature T.

As a variant it could be provided for the adaptation module 30 todetermine the control to apply to the selector 32 on the basis of thefrequency setting F_(set) applied to the frequency actuator 6. Forexample, in a system in which two frequency settings are provided (lowfrequency and high frequency), the adaptation module 30 may control theapplication of the multiplier K₁ when the setting corresponds to the lowfrequency and the application of the multiplier K₂ or K₃ (according tothe measured temperature T) when the setting corresponds to the highfrequency.

FIG. 4 represents a second embodiment of the controller of 12 of FIG. 2.

In this embodiment, the error signal E is applied to a multiplier 44 ofcoefficient K_(i) (for example fixed). The output of the multiplier 44is applied to an adder 46 which also receives as input a version whichis delayed (using a memory 48) from its output U.

The memory 48 is for example produced in the form of a register having apredetermined size (for example 8 bits).

The controller also comprises an adaptation module 40 which makes itpossible to force the value contained in the memory 48 to apredetermined value, for example when the adaptation module 40 detects adownward change in frequency setting F_(set).

The predetermined value written by the adaptation module 40 on detectionof a downward jump in frequency setting may however be variable,according to the new frequency setting: the adaptation module 40 may forexample store, in a look-up table, a predetermined value to write in thememory 48 for each of a plurality of ranges of frequency setting valueF_(set), or for a set of successive control times subsequent to thejump.

The coefficient K_(i) of the multiplier 44, which is fixed in theexample described here, is for example chosen so as to avoid anexceedance of the setting at the time of an upward jump in frequencysetting (that is to say that the new frequency setting is greater thanthe prior frequency setting) in the operating conditions envisioned forthe system. It is to be noted that, at the time of such an upward jumpin frequency setting, the adaptation module 40 does not act on thememory 48 such that the controller 12 operates so as to make themeasured frequency F_(meas) converge towards the frequency settingF_(set) (starting from the actual frequency prior to the frequencyjump).

At the time of such an upward jump (or positive jump), the controlsignal is thus governed as follows: U(k)=K_(i)·E(k)+U(k−1).

On the other hand, when the adaptation module 40 detects a downward jumpin frequency setting F_(set) (or negative jump, that is to say that thenew frequency setting is less than the prior frequency setting), theadaptation module forces the value in memory 48 to a predetermined valueU₀ (which depends for example as explained above on the new settingF_(set)).

At the time k following the jump, the control signal U(k) thus has thevalue: U(k)=K_(i)·E(k)+U₀.

The predetermined value U₀ is chosen, for example at the time the systemis designed, such that the new control value U(k) leads, afterapplication to the oscillator 14, to a clock having a frequency equal toor less than the new setting F_(set) according to the parametersprovided for the operation of the system, in particular the coefficientK_(DCO) already mentioned for the oscillator 14. It is noted that, whenthe established regime (corresponding to a situation in which the outputfrequency has attained the setting and no longer changes) was attainedbefore application of the setting change, the value of the error signalE at the time of the jump in principle corresponds at that time to thedifference between the new setting and the prior setting.

Naturally, the temporal behavior of the actual frequency generated bythe oscillator 14 on account of the control U(k) does not preciselycorrespond to the temporal behavior expected further to the applicationof the new frequency setting F_(set), in particular on account of driftsthat are present relative to the theoretical operation, and on accountof the modification of the value in memory via the adaptation module 40.The actual clock frequency F_(appl) generated by the oscillator 14 willhowever converge towards the frequency setting F_(cons) on account ofthe resumption in integrator operation by the controller 12, for exampleaccording to the formula U(k+1)=K_(i)·E(k+1)+U(k) at the following time(k+1).

It may be specified here in this connection that the adaptation module40 only forces the value in the memory 48 to the predetermined value U₀at the time at which the downward setting jump F_(set) is detected. Therest of the time, the memory 48 receivers the value output from theadder 46 as already indicated.

It may be understood that, the predetermined value U₀ being chosen togenerate a clock frequency in theory equal to that of the settingF_(set), the actual frequency F_(appl) generated in practice rapidlyconverges towards the setting F_(set), the response (or convergence)time of the frequency actuator varying accordingly.

Furthermore, it is of no importance that the frequency actuallygenerated on application of the predetermined value U₀ to the memory 48is greater than or less than the setting F_(set) envisioned since thevoltage V_(appl) applied at the time of the jump is as already statedsufficient to ensure error-free operation of the electronic circuit 8even at frequencies greater than the new frequency setting F_(set).(Typically, the voltage V_(appl) applied at the time of the jump is thatpreviously applied for safe operation with the prior setting, which isgreater than the new setting in the case of the downward jump envisionedhere.)

FIG. 5 represents a third embodiment of the controller of 12 of FIG. 2.

In this embodiment, the error signal E is applied to a multiplier 54 ofcoefficient K_(i) which is variable under the control of an adaptationmodule 50.

The signal output from the multiplier 54 is applied to an adder 56,which also receives as input its own output U delayed using a memory 58.

As previously, the signal U output from the adder 56 is applied to theoscillator 14.

In this embodiment it is provided for the adaptation module 50 toreceive both the frequency setting F_(set) and the measured frequencyF_(meas).

On detection of a positive setting jump (that is to say an increase inthe setting) by the adaptation module 50 (that is to say a variation inthe setting F_(set) that it receives), the adaptation module measuresthe actual convergence time t_(conv) of the frequency towards itssetting, that is to say for example the time taken (from the detectionof the frequency jump) by the measured frequency signal F_(meas) to freach the setting, to the nearest given percentage (for example to thenearest 5%).

The adaptation module 50 also determines whether, during the convergencetime, the measured frequency F_(meas) goes beyond the new frequencysetting F_(cons).

Once the convergence time has been measured and the existence of anyexceedance has been determined, the adaptation module 50 modifies thecoefficient K_(i) of the multiplier 54 as follows:

if the adaptation module 50 has found the existence of an exceedance ofthe setting F_(set), the gain K_(i) is rendered by a predefinedincrement d_(K);

if no exceedance is detected and the convergence time t_(conv) is lessthan a first predetermined time t₀ (minimum acceptable), the gain isalso rendered by a predefined increment, for example the same incrementd_(K);

if no exceedance is detected and the convergence time t_(conv) isgreater than a second predetermined time t₁ (maximum acceptable), thegain K_(i) is increased by a predefined increment, for example equal tothe increment t_(K) already mentioned.

Thus, the value of the gain K_(i) will be continually adapted so as toavoid an exceedance of the frequency setting F_(set) and to obtain aconvergence time comprised between the predetermined times t₀ and t₁.

It is to be noted that the procedure which has just been described isapplied in the case of a positive jump in setting due to the fact thatit is wished to avoid the exceedance of the setting for this type ofjump, as already explained.

A similar procedure could also be applied to a negative jump in settingin order to continually adapt the convergence time. The procedure couldthen be applied after a first modification to the gain K_(i) (in orderto use an initial gain adapted to the negative jump) in accordance withthe embodiment of FIGS. 3A and 3B.

The frequency response time of the actuator may thus be varied accordingto the direction of variation of the setting.

FIG. 6 illustrates another embodiment of the invention.

This embodiment is based on a closed-loop architecture as describedabove with reference to FIG. 2.

In this embodiment, an adaptation module 60 receives the frequencysetting values F_(set) and the error values E (already introduced in thecontext of FIG. 2) and on that basis generates a gain K_(i) which itsends to the controller 12 in order for the latter to apply that gainK_(i) to the error signal E.

The present embodiment is moreover based on an operation of modeling thedifferent blocks by means of a transfer function of z, as represented inFIG. 6.

The closed loop transfer function (that is to say that of the system inFIG. 6 as a whole) is written:

$\mspace{79mu}{\frac{F_{appl}(z)}{F_{set}(z)} = \frac{K_{I}K_{DCO}}{1 - {\left( {1 - {K_{I}K_{DCO}K_{S}}} \right)z^{- 1}}}}$     and$\frac{E(z)}{F_{setting}(z)} = {\frac{1}{1 + \frac{K_{I}K_{DCO}K_{S}}{\left( {z - 1} \right)}} = {\frac{z - 1}{z - \left( {1 - {K_{I}K_{DCO}K_{S}}} \right)} = {\frac{1 - z^{- 1}}{1 - {\left( {1 - {K_{I}K_{DCO}K_{S}}} \right)z^{- 1}}}.}}}$

By denoting E(k) and F_(set)(k) as the values of the error signal E andof the frequency setting F_(set) at the time k, the following temporalexpression is obtained for the error e(k):E(k)=F _(setting)(k)−F _(setting)(k−1)+(1−K _(I) K _(DCO) K_(S))·E(k−1).

The case is taken for example in which the system has attained a stateof equilibrium at a given time (here denoted k=−1), i.e. E(−1)=0, and inwhich, at a given time (k=0), the setting is modified stepwise, i.e.F_(set)(0)−F_(set)(−1)=ΔF . We thus have: E(0)=ΔF.

At the following time (k=1), we have F _(set)(1)−F _(set)(0)=0 (onaccount of the step form of the setting) and:E(1)=(1−K _(I) K _(DCO) K _(S))·E(0)=(1−K _(I) K _(DCO) K _(S))·ΔF.

By measuring E(1) and taking into account the fact that E(0) is equal tothe change in setting, the adaptation module may compute the gainK_(DCO) by:

$K_{DCO} = {\frac{\left( {1 - \frac{E(1)}{\Delta\; F}} \right)}{K_{I}K_{S}}.}$

It is to be noted that in established operating regime, the gain K_(I)is known by the adaptation module 60 (since it is generated andcontrolled by that module as described below). A fixed initializationvalue may furthermore be provided. As regards the gain K_(S) of thesensor 16, this is constant and may thus be considered as a fixed valueof the system, stored for example at the adaptation module 16.

The gain K_(DCO) of the oscillator 14 is thus computed on the basis ofthe measurement of the input signal E(1) at a frequency jump, withoutopening the feedback control/regulation loop, and without having to taketwo measurement points.

It is noted that the above also applies when the change in setting isnot a step, taking into account the particular successive values of thefrequency setting.

Several measurement points may moreover be used. In that case it is thena matter of minimizing a quadratic criterion which depends on the gainK_(DCO), the other parameters K_(I) and K_(S) being considered to beknown. A non-linear programming method may for example be implemented,as described in the work “Practical methods of optimization”, R.Fletcher, 2^(nd) edition, Wiley, ISBN 13: 978 0 471 91547 8. A leastsquares error method may also be implemented, which is non-optimal inthis case since the problem is not linear in K), but for which theresult will be entirely satisfactory if the hypothesis is made that thenoise level is low.

Whatever the determination technique used, it is possible to determine,thanks to the knowledge of the gain of the oscillator 14, the gain K_(I)to use at the time of the following jump to obtain a particular shapefor the response as follows.

By considering the equations reviewed above, it is found that the pole αof the closed loop system is written: α=1−K_(I)K_(DCO)K_(S). Yet thispole is directly linked to the shape of the desired response, that is tosay to the response time, for example at 5%, and to the transient shapeof the temporal response (see on this subject the work “Analyse desSystèmes linéaires”, (a translation of this French title being “Analysisof non-linear systems”), under the direction of Ph. de Larminat,collection I2C, Hermes, ISBN 2-7462-0491-6).

It is provided to use predetermined values for the pole α, that arecharacteristic of the response shape, here a predetermined value α_(P)for the positive setting jumps and a predetermined value α_(N) for thenegative setting jumps (the differentiation between positive jump andnegative jump being useful for the reasons already set out above).

Thus, when the adaptation module 60 detects a positive setting jumpF_(set), it actuates the controller 12 to use a gain

${K_{I} = \frac{1 - \alpha_{P}}{K_{DCO}K_{S}}};$on the other hand, when the adaptation module 60 detects a negativesetting jump F_(set), it actuates the controller 12 to use a gain

$K_{I} = {\frac{1 - \alpha_{N}}{K_{DCO}K_{S}}.}$It is noted that, in both cases, the value of the gain K_(DCO) used isthat determined as indicated above by measurement at the previous jump(a default value may naturally be used if no measurement has been madepreviously, for example on initialization of the process).

The foregoing embodiments are merely possible examples of implementationof the invention, which is not limited thereto.

For example, the determination of the oscillator gain K_(DCO) bymeasurement, presented with reference to FIG. 6, could be used in thecontext of the embodiment of FIG. 4, which would make it possible tovary the value U₀ according to the gain K_(DCO) determined (the value U₀chosen depending in particular on the oscillator gain K_(DCO) asindicated above).

The invention claimed is:
 1. A synchronous digital electronic circuit inwhich timing is provided with a clock signal having a clock frequency,the device comprising: a frequency actuator comprising a controller andincluding an oscillator controlled by a control signal generated by thecontroller and that generates the clock signal according to a frequencysetting using a regulation mechanism, wherein the controller receives anerror signal obtained by a difference between the frequency setting anda measured frequency of the clock signal, the controller beingconfigured to apply a gain to the error signal; a control module thatselectively applies a first frequency setting or a second frequencysetting higher than the first setting to the frequency actuator; and anadaptation module configured to modify the regulation mechanismaccording to the applied frequency setting by controlling the gainapplied by the controller, such that when the frequency setting isincreased, the gain applied by the controller decreases for increasingthe response time of the frequency actuator, and when the frequencysetting is decreased, the gain applied by the controller increases fordecreasing the response time of the frequency actuator.
 2. The deviceaccording to claim 1, wherein the adaptation module controls the gainapplied by the controller according to the gain of the oscillator. 3.The device according to claim 1, wherein the adaptation module isconfigured to modify an operating parameter of the controller.
 4. Asupply device according to one of claim 1, wherein the controller isconfigured to apply a gain to the error signal.
 5. The device accordingto claim 4, wherein the adaptation module is configured to control thegain applied to the error signal.
 6. The device according to claim 5,wherein a selector controlled by the adaptation module is configured toselectively apply the error signal to a selected multiplier from among aplurality of multipliers.
 7. The device according to claim 6, whereinthe controller comprises a memory configured to store a control valueand the adaptation module stores in the memory a predetermined value ondetection of a setting jump.
 8. The device according to claim 1, furthercomprising a voltage actuator configured to generate a voltage accordingto a voltage setting adapted to the frequency setting, on application ofthe frequency setting to the frequency actuator.
 9. A synchronousdigital electronic circuit in which timing is provided with a clocksignal having a clock frequency, the device comprising: a frequencyactuator comprising a controller and including an oscillator controlledby a control signal generated by the controller and that generates theclock signal according to a frequency setting using a regulationmechanism, a control module that selectively applies a first frequencysetting or a second frequency setting higher than the first setting tothe frequency actuator; and an adaptation module configured to modifythe regulation mechanism according to the applied frequency setting bycontrolling the gain applied by the oscillator such that when thefrequency setting is increased, the gain applied by the oscillatordecreases for increasing the response time of the frequency actuator,and when the frequency setting is decreased, the gain applied by theoscillator increases for decreasing the response time of the frequencyactuator.